Airplane propeller



J. F. FRITZ AIRPLANE PROPELLER March 22, 1932.

' Fil ed Nov. 24, 1950 Patented Mar. 22, 1932 UNETED STATES JOHN F.FRITZ, OF EVERGREEN PARK, ILLINOIS AIRPLANE PROPELLER Application filedNovember 24, 1930. Serial-No. 497,882.

My invention relates to airplane propellers, and more particularly tothe construction of the blades thereof, and my main object is to providea propeller whose blade is designed to more fully engage the airdisplaced by the propeller.

A further object of the invention is to construct the blade of the novelpropeller on dual lines, whereby to provide an auxiliary blade to followup the action of the main blade.

A still further object of the invention is to lend the auxiliary bladeof the novel propeller a curvature designed to pocket or retain the airdissipated by the main propeller blade, and so save such air for theaction of the next propeller blade.

A final but nevertheless important object of the invention is to designthe novel propeller blade in a single and rugged piece,

whereby to provide maximum strength and rigidity.

With the above objects in view and any others that may suggestthemselves from the specification and claims to follow, a betterunderstanding of the invention may be had by reference to theaccompanying drawings, in which Fig. 1 is an elevation of the novelpropeller blade; I

Fig. 2 is an edge view thereof from the right hand side of Fig. 1;

Fig. 3 is a rear elevation of the propeller blade;

Fig. 4: is an edge view opposite from that of Fig. 2, and Fig. 5 is asection on the line 55 of Fig. 1.

It is a well known scientific fact that the conventional propellerdissipates a great deal of air during its action, so that it only has afraction of the proper efliciency during progress. Consequently, thepropeller must be raced or spun at a high rate of -speed in order tocreate suflicient propulsive force to induce a take-off of the craft orto keep the same in motion. Various attempts have been made to alter thedesign of the propellers for the recovery of the lost motion or powerreferred to, but few attempts have resulted in g In carrying out theobjects aforesaid, I

use the standard propeller as a basis, the blade thereof'being indicatedat 10 in the drawings. However, I enlargethe hub portionll of thepropeller sufiiciently to form an auxiliary blade 12 spaced insubstantial parallelism from the main blade and connected with its outerend to the same by an integral spacer or connection 13. The main bladeis made with a shallow recess 14 in one of its edges, and has theconventional pitch and curvature. On the other hand, the auxiliary blade12 has a hollow curvature as indicated in Figure 5 and is somewhatfanshaped as shown in Figure 3. One of its sides overlaps the recessedportion 14 of the main blade spacedly.

In the action of the propeller, it is intended to rotate in thedirection of the horizontal arrow in Figure 1. In doing this, the mainblade displaces the body of air, while the auxiliary one pockets a bodyof air. Thus, considering that the speed of the propeller is ample evenat the ordinary rate, it will be seen that the body of air displaced byone propeller blade will be caught and pocketed by the auxiliary bladeof the next oncoming blade, so that it may be used for purposes ofdisplacement in the line of travel rather than dissipation in a lateralor wasteful course. The dual propeller is not only a propeller withtwice the number of blades, but a propeller with blades which carrytheir own and immediate retaining members.

It will be seen that a propeller of the above description in action willdisplace a much greater amount of air along the course of travel withoutbeing run at excessive speeds. Thus, a take-off may be effected withoutracing the engines of; the craft and straining the latter unduly in aneffort to gain lifting force. Obviously, my propeller is designed tosave the engines from excessive vibration, wear and tear and waste offuel, as well as to accomplish without extra parts or mechanisms amarked increaseof efiiciency for the propeller.

I claim 1. A propeller formed with a main blade, an auxiliary bladeadjoining the latter, both blades being integral extensions from the 100propeller hub, the auxiliary blade extending radially in a fan-like formand with a transverse curvature presenting its hollow inwardly, and anintegral reduction extended owns versely from the outer portion of theauxiliary blade to meet and join the main blade. 2. Apropeller formedwith a main blade, and an auxiliary Blade adjoining the; latter, saidadjoiningfbl'ade having a transverse our- 10 vature with the hollowfacing the main blade, and the latter beingr'zneoessed in edge: withinthe expanse of the corresponding portions of the adjoining blade.

3. A propellerformed with a main blade, 15 and an auxiliary bladeadjoining the latter,

said. adjoining blade having a transverse I Curvature with the: hollowfacing. the. main 7 blade, the latter'heing recessed in its. rear "edgewithintheexpanse. of the correspond- 30 ihg portions ofQtlie adioining,blade, andx said recess being oflarcuate profile Inrtestimonywhereofilaifix my signature. a i 7 JOHN F. FRITZ.

